Field of the Invention
This invention relates to systems and methods for dynamically modifying data set generation depth in PDSE data sets.
Background of the Invention
In the z/OS operating system, PDSE (partitioned data set extended) data sets are used to simply and efficiently organize related groups of sequential files, also referred as “members.” Current versions of PDSE data sets may support multiple levels, or generations, of members. Using this feature, when a member is changed, a new member may be created and the older version of the member may be retained, up to a specified number of generations. This feature advantageously enables recent changes to a member to be reversed. This feature also allows multiple generations of a member to be retained for archival reasons. The retained generations may be structured in a first in, first out (FIFO) configuration, such that an oldest generation is discarded when the retained generation limit is reached.
PDSE data sets may be configured to store previous versions of individual members up to a predefined maximum generational limit. Under the current PDSE implementation which uses a set maximum generations parameter, frequently updated members are constantly expunging viable older versions, while infrequently updated members retain previous versions far past their usefulness. Simply increasing the maximum generations parameter is often not a viable option due to the increase in space consumption. Using this option, members that are infrequently updated will still store as many generations as those that are frequently updated. This represents an inefficient use of space in a PDSE data set.
In view of the foregoing, systems and methods are needed to dynamically modify generation depth in PDSE data sets. Further needed are systems and methods to retain additional generations for members that are updated frequently, while retaining fewer generation for members that are updated less frequently. Ideally, such systems and methods will more efficiently utilize space in PDSE data sets.